Institute of
Physiology and 1 Institute of Animal Hygiene, FML-Weihenstephan, Center
of Life and Food Science,Technical
University of Munich, Freising-Weihenstephan, Germany

Aim. To quantify the
expression of Fc receptor (FcRn) and polymeric immunoglobulin receptor
(pIgR) mRNA under along-term influence of
mycotoxinmycophenolic acid (MPA),which is used in human
transplantationmedicine due toits immunosuppressive properties
and is a common contaminant in silage.

Results.
Each tissue exhibited an individual expression pattern of FcRn and
pIgRmRNA. Both types of Ig receptors werehighly expressed in the liver,
kidney, and gastrointestinal tract.Medium-to-low expressions were found
in the spleen,thymus, mesenteric and pharyngeal
lymph nodes. FcRn mRNA was significantly down-regulated byMPA in the
liver(p=0.02).
After MPA treatment, a significant up-regulation of pIgR mRNA
expression was observed in the ileum andliver (p=0.04 for both).
Expression level of FcRn mRNA in the tissues in decreasing order was as
follows: liver>kidney>jejunum>ileum>spleen>thymus>mesenterial
lymph node>pharyngeal lymph node;whereas expressionlevel for pIgRmRNAwas the
following: liver>kidney>jejunum>ileum>pharyngeal lymph
node>spleen> thymus >
mesenterial lymph node.

Conclusion. The MPA exhibited immunomodulatory effects in
the liver and ileum of treated sheep. Its possibleimmunosuppressive effectsmay be
explained by lowering the level of FcRn expression in the liver,which
resulted in alower IgG serum-to-bile transport.
However, MPA showed stimulatory effects on pIgR expression in
the liver and ileum,suggesting good IgA and IgM
transport in these tissues.